U.S. patent number 11,064,868 [Application Number 16/052,209] was granted by the patent office on 2021-07-20 for endoscope with distal linear conductor.
This patent grant is currently assigned to PANASONIC I-PRO SENSING SOLUTIONS CO., LTD.. The grantee listed for this patent is PANASONIC I-PRO SENSING SOLUTIONS CO., LTD.. Invention is credited to Hirofumi Enomoto, Kouichi Hoshino, Katsuhiro Kobayashi.
United States Patent |
11,064,868 |
Kobayashi , et al. |
July 20, 2021 |
Endoscope with distal linear conductor
Abstract
An endoscope includes an insertion portion that has a tip
portion to be inserted into an examination target from a tip side
of the tip portion. The endoscope includes a lens unit that is
disposed at the tip portion. The endoscope includes an image sensor
that is disposed on an opposite side to the tip side of tip portion
with respect to the lens unit. The endoscope includes a linear
conductor that has a tip disposed at the tip side with respect to
the image sensor and has a proximal end which is extended from the
tip through inside the insertion portion.
Inventors: |
Kobayashi; Katsuhiro (Fukuoka,
JP), Enomoto; Hirofumi (Fukuoka, JP),
Hoshino; Kouichi (Fukuoka, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
PANASONIC I-PRO SENSING SOLUTIONS CO., LTD. |
Fukuoka |
N/A |
JP |
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Assignee: |
PANASONIC I-PRO SENSING SOLUTIONS
CO., LTD. (Fukuoka, JP)
|
Family
ID: |
1000005686012 |
Appl.
No.: |
16/052,209 |
Filed: |
August 1, 2018 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20190038112 A1 |
Feb 7, 2019 |
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Foreign Application Priority Data
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Aug 2, 2017 [JP] |
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JP2017-150016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02B
23/2484 (20130101); A61B 1/00096 (20130101); A61B
1/05 (20130101); G02B 23/2423 (20130101); A61B
1/0008 (20130101); G02B 23/2476 (20130101); A61B
1/00165 (20130101); A61B 1/307 (20130101); A61B
1/233 (20130101); A61B 1/07 (20130101); A61B
1/3137 (20130101); A61B 1/267 (20130101) |
Current International
Class: |
A61B
1/00 (20060101); A61B 1/05 (20060101); G02B
23/24 (20060101); A61B 1/313 (20060101); A61B
1/233 (20060101); A61B 1/07 (20060101); A61B
1/267 (20060101); A61B 1/307 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2004-148028 |
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May 2004 |
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JP |
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2013-198566 |
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Oct 2013 |
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JP |
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2017-047168 |
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Mar 2017 |
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JP |
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WO2013/031276 |
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Mar 2013 |
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WO |
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2016/203830 |
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Dec 2016 |
|
WO |
|
Other References
Search Report issued in European Patent Office (EPO) Patent
Application No. 18186023.0, dated Jan. 7, 2019. cited by applicant
.
Office Action issued in Japanese Counterpart Patent Appl. No.
2017-150016, dated Mar. 9, 2021, along with an English translation
thereof. cited by applicant.
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Primary Examiner: Neal; Timothy J
Assistant Examiner: Chou; William B
Attorney, Agent or Firm: Greenblum & Bernstein
P.L.C.
Claims
What is claimed is:
1. An endoscope comprising: an insertion portion that has a tip
portion to be inserted into an examination target from a tip side
of the tip portion; a lens that is disposed at the tip portion; a
tip flange portion that is disposed on a front outermost surface of
the tip portion and has electrical conductivity, wherein an
internal diameter hole of the tip flange portion supports a part of
the lens at the tip side; an image sensor that is disposed on an
opposite side to the tip side of the tip portion with respect to
the lens; an electrically-insulative circuit; and a linear
conductor electrically connected to the electrically-insulative
circuit via an insulated earth line, and that has a tip disposed at
the tip side with respect to the image sensor and has a proximal
end which is extended from the tip through inside the insertion
portion, wherein the tip of the linear conductor and the tip flange
portion are electrically connected to each other.
2. The endoscope according to claim 1, wherein the tip of the
linear conductor and the tip flange portion are disposed so as to
be separated from each other.
3. The endoscope according to claim 2, wherein the tip of the
linear conductor and the tip flange portion are fixed to each other
with an adhesive.
4. The endoscope according to claim 2, wherein the tip of the
linear conductor extends along a part of circumferential surface of
the lens in a circumferential direction.
5. The endoscope according to claim 2, wherein the tip of the
linear conductor extends along an entire circumference of the lens
in a circumferential direction.
6. The endoscope according to claim 2, wherein the tip of the
linear conductor and the tip flange portion are disposed so as to
be separated from each other by a resin.
7. The endoscope according to claim 1, wherein the tip of the
linear conductor is disposed between an outer periphery of a
circular lens and a corner portion of the image sensor, and wherein
the circular lens is surrounded by an angular outline of the image
sensor.
8. The endoscope according to claim 1, wherein an outer periphery
of the lens is molded by a mold portion, and wherein at least a
portion of the tip of the linear conductor is covered with the mold
portion.
9. The endoscope according to claim 1, wherein an outer periphery
of the lens is molded by a mold portion, and wherein the tip of the
linear conductor is disposed outside the mold portion.
10. The endoscope according to claim 1, further comprising: a
protective element that is disposed between the linear conductor,
wherein the electrically-insulative circuit is electrically
insulated from the tip portion.
11. The endoscope according to claim 10, wherein the protective
element cuts off a leakage current leaking in the tip portion.
12. The endoscope according to claim 1, wherein the
electrically-insulative circuit is a protected circuit that
prevents an electric shock to a patient.
13. The endoscope according to claim 1, wherein the
electrically-insulative circuit suppresses static electricity from
the tip portion.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present disclosure relates to an endoscope.
2. Description of the Related Art
In recent years, in the medical field or the industrial field,
endoscopes for imaging an observation target (for example, the
inside of a patient's body or the inside of an apparatus or a
structure) have become widespread. In this type of endoscope, in an
insertion portion on a tip side to be inserted into the inside of
an observation target, light from an imaging region is focused on a
light-receiving surface of an image sensor by an objective lens
system. The endoscope converts the focused light into electrical
signals, and sends the electrical signals to an external image
processor or the like as video signals via a signal cable.
For example, in endoscopes to be used in the medical field, in
order to alleviate a patient's burden, it is important to further
reduce the external diameter of the insertion portion on the tip
side to be inserted into the inside of a patient's body or the
like. In the related art, oral endoscopes having a normal diameter
had a maximum external diameter of about 8 to 9 mm. For this
reason, there was a case where a tongue base was likely to be
touched during insertion and a patient are accompanied by nausea or
stuffiness. Thus, in recent years, fine-diameter transnasal
endoscopes have rapidly spread. In the fine-diameter transnasal
endoscopes, the maximum external diameter is about 5 to 6 mm of
about half of the related-art oral endoscopes. For this reason, in
the fine-diameter transnasal endoscopes, transnasal insertion is
possible. As a result, in cooperation with being as thin as about 5
mm, in many cases, vomiting reflex is little and insertion is also
not bothered too much.
Here, in endoscopes into which an imaging unit including an
objective lens system, an image sensor, and the like are
incorporated, for example, WO2013/031276 suggests an endoscope that
displays an image (endoscopic image) obtained by imaging the
observation target on a display device, such as an external
monitor.
Main portions of an endoscope 501 disclosed in WO2013/031276 are
illustrated in FIG. 14. FIG. 14 is a sectional view illustrating
the configuration of a tip portion of the related-art endoscope
501.
An imaging unit 505 is built in a tip rigid portion 503 of the
endoscope 501. The imaging unit 505 has an objective lens group
507, and a substantially tubular lens frame 509 that is a fixing
frame holding the objective lens group 507. In the imaging unit
505, imaging light on an optical axis O incident on the objective
lens group 507 is focused on a light receiving portion 513 of a
solid-state image sensor 511.
In the endoscope 501, the tip rigid portion 503 of a tip portion
515 is formed of non-conductive hard resin. Additionally, the
endoscope 501 is provided with a pipe 517 made of resin, such as
rubber, which is provided continuously with the rear of the tip
rigid portion 503, and a metallic pipe 519 disposed on an inner
surface of the resin pipe 517.
The tip rigid portion 503 includes two projection portions 521 that
extend upward and downward. The projection portions 521 extend to
two upper and lower locations so as to approach the metallic pipe
519 in a contactless manner, and a separation distance G thereof
from the metallic pipe 519 is set to about 0.2 mm.
In the endoscope 501 configured as described above, static
electricity from the tip rigid portion 503 is discharged to the
metallic pipe 519 via the two projection portions 521. Then,
electric charges of the applied static electricity safely flow from
the metallic pipe 519 or the bending tube of a bending portion to a
ground (GND) of a subsequent state video processor (not
illustrated) through a shield of a flexible tube portion.
Accordingly, the endoscope 501 can be configured such that an
electrical configuration within the tip portion, in this example,
the static electricity toward the solid-state image sensor 511 is
not easily discharged.
The related-art endoscope 501 as shown in WO2013/031276 can be
configured such that the static electricity is not easily
discharged toward the solid-state image sensor 511. However, in the
endoscope 501, the solid-state image sensor 511 is covered with the
substantially tubular lens frame 509, and the outsides of the two
upward and downward extending projection portions 521 of the lens
frame 509 are further surrounded by the metallic pipe 519. For this
reason, there is a possibility that it is difficult to realize a
reduction in size or a reduction in diameter of the insertion tip
portion of the endoscope 501. In other words, there is a
possibility to it is difficult to achieve the compatibility between
protecting the image sensor by allowing the static electricity to
escape and realizing a reduction in size or a reduction in diameter
of the insertion tip portion of the endoscope.
SUMMARY OF THE INVENTION
The present disclosure has been invented in view of the
above-described related-art situation, and an object thereof is to
provide an endoscope in which a reduction in diameter of an
insertion tip portion is facilitated with a simple structure while
an image sensor is protected by allowing static electricity to
escape.
The present disclosure provides an endoscope including an insertion
portion that has at least a tip portion to be inserted into an
examination target from a tip side of the tip portion; a lens unit
that is disposed at the tip portion; an image sensor that is
disposed on an opposite side to the tip side of the tip portion
with respect to the lens unit; and a linear conductor that has a
tip disposed at the tip side with respect to the image sensor and
has a proximal end which is extended from the tip through inside
the insertion portion.
According to the present disclosure, a reduction in diameter of the
insertion tip portion can be facilitated with a simple structure
while the image sensor is protected by allowing the static
electricity to escape.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is an overall configuration view illustrating an example of
an endoscopic system using an endoscope of Embodiment 1.
FIG. 2 is a perspective view illustrating a state in which a tip
portion of the endoscope of Embodiment 1 is seen from a front
side.
FIG. 3 is a side view of the tip portion from which half faces of a
cover tube and a sheath in the endoscope of Embodiment 1 are
removed.
FIG. 4 is a side view of the tip portion from which a mold portion
of Embodiment 1 is omitted.
FIG. 5 is a view as seen from arrow A-A of FIG. 4.
FIG. 6 is a block diagram schematically illustrating the
configuration of the endoscopic system in a case where the
endoscope of Embodiment 1 is used for medical applications.
FIG. 7 is a block diagram schematically illustrating the
configuration of the endoscopic system in a case where the
endoscope of Embodiment 1 is used for industrial applications.
FIG. 8 is a perspective view of main portions of a configuration
example in which a tip of a linear conductor in an endoscope of
Embodiment 3 is disposed in a circumferential direction.
FIG. 9 is a perspective view of main portions of a configuration
example in which the tip of the linear conductor in the endoscope
of Embodiment 3 is disposed at the entire circumference in the
circumferential direction.
FIG. 10 is a perspective view of main portions of a configuration
example in which a linear tip of a linear conductor in an endoscope
of Embodiment 4 is disposed outside a mold portion.
FIG. 11 is a perspective view of main portions of a configuration
example in which a circumferential tip of the linear conductor in
an endoscope of Embodiment 4 is disposed outside the mold
portion.
FIG. 12 is a block diagram schematically illustrating the
configuration of an endoscopic system in a case where an endoscope
of Embodiment 5 is used for medical applications.
FIG. 13A is a block diagram schematically illustrating a first
usage example of an ESD suppressor related to a comparative
example.
FIG. 13B is a block diagram schematically illustrating a second
usage example of an ESD suppressor related to Embodiment 5.
FIG. 14 is a sectional view illustrating the configuration of a tip
portion of a related-art endoscope.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Background Leading to Contents of Respective Embodiments
Compared to the maximum external diameter of the above-described
oral endoscopes and fine-diameter transnasal endoscopes, in recent
years, in order to observe the inside of an ultrafine diameter
region (for example, the inside of a blood vessel of a human body)
that cannot be inserted within the related-art oral endoscopes and
fine-diameter transnasal endoscopes, development of a further
reduction in diameter is important. For example, a high-quality
endoscope in which the maximum external diameter of an insertion
tip portion capable of observing the inside of the blood vessel of
the human body, or the like, is 2 mm or less is required.
Additionally, as an existing endoscope, for example, there is known
a fiber mirror type endoscope in which an insertion tip portion is
not provided with an image sensor (that is, an image sensor), an
optical image is guided from the insertion tip portion to a rear
end side by a bundle of optical fibers, and the optical image is
focused on an image sensor provided on a rear end side that is not
the insertion tip portion. In this type of endoscope, there is an
endoscope of which the maximum external diameter of the insertion
tip portion is 2 mm or less. However, in such a type of endoscope,
restrictions of the thickness and number of optical fibers,
boundary line patterns of optical fibers adjacent to each other in
a captured image are conspicuous. Therefore, it is difficult to
realize the high resolution and high quality of the captured
image.
Meanwhile, in a related-art endoscope like the above-described
WO2013/031276, a gap has provided in a diameter direction of the
insertion tip portion. For this reason, there are manufacturing
problems that the maximum external diameter increases, crushing is
likely to occur due to an external force or bending, it is
difficult to guarantee insulation against static electricity, parts
shapes are complicated, and assembling is difficult. Additionally,
in this related-art endoscope, since the metallic pipe is provided,
similarly, there is a possibility that the maximum external
diameter increases and the flexibility of an insertion portion is
impaired.
Thus, in the respective following embodiments, examples of
endoscopes in which a reduction in diameter of the insertion tip
portion is facilitated with a simple structure while the image
sensor is protected by releasing static electricity will be
described.
Hereinafter, the respective embodiments specifically disclosing the
endoscopes of the present disclosure will be described in detail,
referring to the drawings appropriately. However, there is a case
where detailed description more than needed is omitted. For
example, there is a case where detailed description of already
well-known matters and duplicate description of substantially the
same configuration are omitted. This is to avoid unnecessary
redundancy of the following description and facilitate
understanding by those skilled in the art. In addition, the
accompanying drawings and the following description are provided so
that those skilled in the art sufficiently understand the present
disclosure, and are not intended to limit the subject matter
described in the claims by these drawings and description.
Embodiment 1
FIG. 1 is an overall configuration view illustrating an example of
an endoscopic system 11 using an endoscope 100 of Embodiment 1. In
FIG. 1, the overall configuration of the endoscopic system 11
including the endoscope 100 and a video processor 13 are
illustrated in a perspective view.
In addition, directions to be used for description in the present
specification follow description of directions in the respective
drawings. Here, the "up" and the "down" correspond to above and
below the video processor 13 placed on a horizontal plane,
respectively, and the "front (tip)" and the "rear" correspond to a
tip side of an insertion portion 15 of an endoscope body
(hereinafter referred to as an "endoscope" and a proximal end side
(in other words, a video processor 13 side) of a plug 17,
respectively.
As illustrated in FIG. 1, the endoscopic system 11 is configured to
include, for example, the endoscope 100 that is a medical flexible
endoscope, and the video processor 13 that performs well-known
image processing or the like on a still image or a moving image
captured by imaging the inside of an observation target (for
example, the blood vessel of the human body) serving as an example
of an examination target. The endoscope 100 extends substantially
in a forward-rearward direction, and includes the insertion portion
15 to be inserted into the inside of the observation target, and
the plug 17 to which a rear portion of the insertion portion 15 is
connected.
The video processor 13 has a socket 21 that opens in a front wall
19. A rear portion of the plug 17 of the endoscope 100 is inserted
into the socket 21. Accordingly, the endoscope 100 is capable of
transmitting and receiving electrical power and various signals
(video signals, control signals, and the like) between the
endoscope 100 and the video processor 13.
The above-described electrical power and various signals are
transmitted from the plug 17 to a flexible portion 23 via a
transmission cable 25 (refer to FIG. 3 or 4) inserted through the
inside of the flexible portion 23. Image data captured by the image
sensor 29 (that is, the image sensor) provided in a tip portion 27
is transmitted from the plug 17 to the video processor 13 via the
transmission cable 25. The video processor 13 performs well-known
image processing, such as color correction and grayscale
correction, on the image data transmitted from the plug 17, and
outputs the image data after the image processing to a display
device (not illustrated). The display device is, for example, a
monitoring device having a display device, such as a liquid crystal
display panel, and displays an image (for example, data of a still
image or a moving image showing a state within a blood vessel of a
person who is a subject) of a subject imaged by the endoscope
100.
The insertion portion 15 has the flexible portion 23 of which a
rear end is connected to the plug 17, and the tip portion 27
connected to a tip of the flexible portion 23. The flexible portion
23 has a suitable length corresponding to methods, such as various
kinds of endoscopy or endoscopic surgery, and an outer periphery of
the flexible portion 23 is covered with, for example, a sheath. The
flexible portion 23 connects the tip portion 27 and the plug 17 to
each other.
The endoscope 100 of Embodiment 1 to be described below is capable
of being inserted into a fine-diameter body cavity by providing the
external diameter of the tip portion 27 with a fine diameter. The
fine-diameter body cavity is not limited to a blood vessel of a
human body, and includes, for example, a ureter, a pancreatic duct,
a bile duct, bronchioles, and the like. That is, the endoscope 100
is capable of being inserted into the blood vessel, a ureter, a
pancreatic duct, a bile duct, a bronchus, and the like of a human
body. In other words, the endoscope 100 can be used for observation
of a lesion within the examination target (for example, a blood
vessel), for example, as medical applications. The endoscope 100 is
also effective in identifying atherosclerotic plaque. Additionally,
the endoscope 100 is also applicable to endoscopic observation at
the time of cardiac catheterization examination. Moreover, the
endoscope 100 is also effective in detection of thrombus or
arteriosclerotic yellow plaque. In addition, an arteriosclerotic
lesion, a color tone (white, pale yellow, or yellow) and a surface
(smoothness or irregularity) are observed. In the thrombus, a color
tone (red, white, dark red, yellow, brown, or mixed color) is
observed.
Additionally, the endoscope 100 can be used for diagnosis and
treatment of the renal pelvis and ureter cancer, and idiopathic
renal bleeding. In this case, the endoscope 100 can be inserted
into the bladder from the urethra and can be further advanced even
into the ureter to observe the inside of the ureter and the renal
pelvis.
Additionally, the endoscope 100 is capable of being inserted into
the Vater's papilla opening to the duodenum. Bile is made from the
liver and passes through the bile duct, and the pancreatic juice is
made from the pancreas and is discharged from the Vater's papilla
in the duodenum through the pancreatic duct. The endoscope 100 is
capable of being inserted from the Vater's papilla, which is an
opening portion of the bile duct and the pancreatic duct, to
observe the bile duct or the pancreatic duct.
Moreover, the endoscope 100 is capable of being inserted into the
bronchus. The endoscope 100 is inserted from the oral cavity or the
nasal cavity of a supine specimen (that is, a patient). The
endoscope 100 passes over the pharynx and the larynx and is
inserted into the trachea while viewing the vocal cords. The
bronchus becomes narrower whenever the bronchus branches. For
example, according to the endoscope 100 having a maximum external
diameter of 2 mm or less, it is possible to check an inner cavity
up to a sub-region bronchus.
FIG. 2 is a perspective view illustrating a state in which the tip
portion 27 of the endoscope 100 of Embodiment 1 is seen from a
front side.
The endoscope 100 has a tip flange portion 33 on a front surface of
the tip portion 27. In the tip flange portion 33, a lens 35 is
exposed, and a plurality (for example, four) optical fibers 39
constituting a light guide 37 are disposed in a state where the
optical fibers are disposed at equal intervals. The rear of the tip
flange portion 33 is covered with a cover tube 41. The rear of the
cover tube 41 is connected to a sheath 43. The cover tube 41 and
the sheath 43 may be integrally molded.
FIG. 3 is a side view of the tip portion 27 from which half faces
of the cover tube 41 and the sheath 43 in the endoscope 100 of
Embodiment 1 are removed.
The cover tube 41 of the tip portion 27 covers a mold portion 45.
The cover tube 41 is formed with the same external diameter as or
substantially the same external diameter as the tip flange portion
33. The cover tube 41 is formed of, for example, metal, resin, or
the like as a material. The cover tube 41 has a total length such
that a tip thereof abuts against a larger-diameter portion 47 of
the tip flange portion 33 and a rear end thereof reaches a tip of a
resin portion or the transmission cable 25 that encapsulates a
conductor connecting portion that joins the image sensor 29 and the
transmission cable 25 together. That is, the mold portion 45 is
covered with the cover tube 41.
In addition, if the distance between the rear end of the cover tube
41 and the image sensor 29 is short in a case where the cover tube
41 is formed using metal, there is a possibility that static
electricity is applied from the rear end of the cover tube 41 to
the image sensor 29. For this reason, it is preferable that the
cover tube 41 has a length such that the rear end thereof is
disposed at a position sufficiently separated from the image sensor
29. Accordingly, since it is ensured that the distance from the
rear end of the cover tube 41 to the image sensor 29 is
sufficiently separated, the application of the static electricity
from the rear end of the cover tube 41 to the image sensor 29 is
suppressed.
The mold portion 45 covered with the cover tube 41 has a
smaller-diameter extending portion 51 that extends rearward of the
mold portion 45. The smaller-diameter extending portion 51 is
molded in a columnar shape and has, for example, four optical
fibers 39 embedded therein. The smaller-diameter extending portion
51 has the four optical fibers 39 embedded inside the transmission
cable 25. Internal diameter sides of the cover tube 41 and the
sheath 43 are fixed to outer peripheries of the mold portion 45 and
the smaller-diameter extending portion 51 with an adhesive (for
example, refer to adhesive SB) or the like. That is, in the
endoscope 100, the tip flange portion 33, the cover tube 41, and
the sheath 43 are coaxially connected together.
In the endoscope 100, at least a portion of a lens unit 53, the
image sensor 29, a portion of the transmission cable 25, and
portions of the optical fibers 39 are covered with and fixed by the
resin of the mold portion 45. The mold portion 45 is made of, for
example, a resin material containing an additive for suppressing
the transmittance of light or the like in order to avoid extra
incident light to a resin material or the like or the image sensor
29. Accordingly, the thickness of the mold portion 45 can be made
small and the size of the endoscope 100 can be reduced. As the
additive, for example, carbon black can be added to a mold resin
material (epoxy-based resin).
The sheath 43 is made of a resin material having flexibility. The
sheath 43 can be provided with a single line, a plurality of wires,
and braided tensile strength wire on an inner peripheral side
thereof for the purpose of imparting strength. As the tensile
strength wire, aramid fiber, such as poly-p-phenylene
terephthalamide fiber, polyarylate fiber, polyparaphenylene
benzobisozazole fiber, polyester fiber, such as a polyethylene
terephthalate fiber, nylon fiber, thin tungsten line, or thin
stainless steel line can be used as an example.
FIG. 4 is a side view of the tip portion 27 from which the mold
portion 45 of Embodiment 1 is omitted.
The tip flange portion 33 is formed of, for example, stainless
steel, and has conductivity. The tip flange portion 33 is formed in
a tubular shape in which the larger-diameter portion 47 and an
angular tube portion 55 are connected together from the tip side.
The larger-diameter portion 47 has fiber holding holes 57 (refer to
FIG. 5) into which the four optical fibers 39 are inserted,
respectively. In addition, the larger-diameter portion 47 of the
tip flange portion 33 is not limited to being formed in an annular
shape as illustrated in FIG. 5, and may be formed, for example, in
each of an elliptical shape, a quadrangular shape, and an octagonal
shape. Particularly in a case where the larger-diameter portion 47
is formed in a quadrangular shape or an octagonal shape, it is
preferable that the larger-diameter portion 47 are chamfered so as
to have rounded portions without forming corner portions of the
quadrangular shape or the octagonal shape as much as possible.
Additionally, the larger-diameter portion 47 of the tip flange
portion 33 may be cut and formed in a D-shape in at least one
point, for example in a portion of an annular structure. Even in
this case, it is preferable that the point cut in the D-shape is
chamfered so as to have a rounded portion without forming a corner
portion as much as possible. The fiber holding holes 57 expose
light emitting end surfaces of the inserted optical fibers 39 to
the front surface of the tip portion 27. Four fiber holding holes
57 are provided, for example, at equal intervals in the
circumferential direction. The optical fibers 39 of which tip sides
are inserted into the fiber holding holes 57 are delivered rearward
along the lens unit 53. The angular tube portion 55 is provided
with an internal diameter hole 59 (refer to FIG. 5) into which the
lens unit 53 is inserted, and the lens unit 53 is inserted into the
internal diameter hole 59. An object side of the lens unit 53 is
supported by the internal diameter hole 59 of the tip flange
portion 33. The tip flange portion 33 coaxially holds the lens unit
53.
The endoscope 100 includes the lens unit 53 that accommodates the
lens 35 in a lens supporting member 61, and the image sensor 29
that has an imaging surface covered with an element cover glass 63
and is disposed on a side opposite to the object side (examination
target side) of the lens unit 53. Additionally, the endoscope 100
further includes a bonding resin that fixes the lens unit 53, in
which an optical axis of the lens 35 is made to coincide with the
center of the imaging surface, and the element cover glass 63.
Additionally, the endoscope 100 further includes the transmission
cable 25 having four electric wires that are respectively connected
to, for example, four conductor connecting portions provided on a
surface (rear end surface) on a side (that is, a rear side)
opposite to the imaging surface of the image sensor 29. The four
conductor connecting portions connect respective corresponding
electric wires to the rear end surface of the image sensor 29, and
are fixed to the rear end surface of the image sensor 29 with a
reinforcing adhesive 29A.
A single or a plurality of lenses 35 that are formed of an optical
medium (for example, glass, resin, or the like), and a diaphragm
(not illustrated) overlapped with the lenses 35 are incorporated
into the lens supporting member 61 along the optical axes. The
diaphragm is provided for adjustment of the amount of incident
light to the lenses 35, and only the light that has passed through
the diaphragm is capable of entering the image sensor 29.
As a metallic material that constitutes the lens supporting member
61, for example, nickel is used. Nickel has a high modulus of
rigidity and relatively high corrosion resistance, and is suitable
as a material that constitutes the tip portion 27. Additionally, it
is preferable that the periphery of the lens supporting member 61
is uniformly covered with resin and the tip portion 27 is subjected
to biocompatible coating before examination or before surgery such
that the nickel constituting the lens supporting member 61 is not
directly exposed from the tip portion 27 at the time of examination
or surgery using the endoscope 100. Instead of nickel, for example,
a copper nickel alloy may be used. The copper nickel alloy also has
a high corrosion resistance and is suitable as a material that
constitutes the tip portion 27. Additionally, as the metallic
material that constitutes the lens supporting member 61, a material
that can be manufactured by electroforming (electroplating) is
preferably selected. Here, the reason why the electroforming is
because the accuracy of dimensions of a member to be manufactured
by the electroforming is as extremely high as less than (so-called
submicron accuracy) 1 .mu.m and variations when a number of members
are manufactured are also small. Additionally, as the metallic
material that constitutes the lens supporting member 61, stainless
steel (for example, SUS316) may be used. It is considered that
stainless steel (called an SUS tube) has high biocompatibility, and
is suitable as, for example, an endoscope to be inserted into a
fine-diameter region, such as a human body's blood vessel. The lens
supporting member 61 is an extremely small member, and the errors
of the internal and external diameter dimensions thereof affects
the optical performance (that is, the quality of a captured image)
of the endoscope 100. By constituting the lens supporting member 61
of, for example, a nickel electroformed tube, the endoscope 100
capable of securing high dimensional accuracy and capturing a
high-quality image irrespective of small diameter is obtained.
The lens supporting member 61 may be a sheet material or the like
in addition to the metal, and the lens supporting member 61 may be
positioned as long as the optical axes of the respective lenses 35
of the lens unit 53 are aligned with each other. If the lens unit
53 is covered with the resin, mutual relative positions of the
respective lenses 35 are fixed. For this reason, the lens
supporting member 61 can be made of a material having a low
strength, a small thickness, and a light weight compared with a
lens barrel used in order to support the plurality of lenses 35 in
the related art. Accordingly, it is possible to contribute to a
reduction in diameter of the tip portion 27 in the endoscope 100.
In addition, the lens supporting member 61 does not exclude using
the same metallic lens barrel as the related art.
The image sensor 29 is constituted of, for example, an imaging
device of a small-sized charge coupled device (CCD) or a
complementary metal-oxide semiconductor (CMOS) having a square
shape as seen from the forward-rearward direction. In the image
sensor 29, the light incident from the outside is focused on the
imaging surface by the lenses 35 accommodated in the lens
supporting member 61. Additionally, in the image sensor 29, the
imaging surface is covered with the element cover glass 63. The
image sensor 29 is formed in an angular shape (for example, a
quadrangular shape). Additionally, the image sensor 29 may not be
limited to being formed in the quadrangular shape and may be
formed, for example, in a hexagonal shape or in an octagonal
shape.
The lens unit 53 and the element cover glass 63 are fixed by a
bonding resin. The bonding resin is constituted of, for example, a
UV thermosetting resin. The bonding resin has translucency. In a
case where the UV thermosetting resin is used as the bonding resin,
an outer surface portion can be cured by ultraviolet radiation, and
the inside of a filling adhesive that cannot be irradiated with
ultraviolet rays can be cured by heat treatment. The bonding resin
fixes the lens unit 53, in which the optical axes are made to
coincide with the center of the imaging surface, to the element
cover glass 63. Accordingly, the lens unit 53 and the image sensor
29 are directly bonded and fixed with the bonding resin, that is,
the lens unit 53 and the image sensor 29 are directly attached to
each other via the bonding resin. Although the bonding resin
requires, for example, the heat treatment in order to obtain final
hardness, the bonding resin is an adhesive of a type in which
curing proceeds to a certain degree of hardness also by ultraviolet
radiation.
In addition, in an endoscope 100, in a case where a light emission
surface of each lens 35 that faces the element cover glass 63 is a
concave surface, an edge portion that is an annular end surface
around the lens 35 is bonded the element cover glass 63. In this
case, an outer periphery of the lens 35 and an outer periphery of
the lens supporting member 61 may also be simultaneously fixed with
the bonding resin. An air space is provided between the lens 35 and
the image sensor 29 as the edge portion of the lens 35 is bonded to
the element cover glass 63. As the air space is provided between
the lens 35 and the image sensor 29, the optical performance of the
lens 35 can be enhanced. For example, the refractive index
difference of the light emitted from the lens 35 to the air space
can be increased, and power for refracting the light is obtained.
Accordingly, optical design, such as enhancing resolution and
increasing the angle of view, is facilitated. As a result, the
quality of an image captured by the endoscope 100 is improved.
A plurality of conductor connecting portions are provided at a rear
portion on a back side of the image sensor 29. The conductor
connecting portions can be formed of, for example, a land grid
array (LGA). The conductor connecting portions include an
electrical power connecting portion and a signal connecting
portion. The conductor connecting portions are electrically
connected to a plurality of electric wires of the transmission
cable 25. The plurality of electric wires include, for example, an
insulated signal line 65, an insulated power source line 67, and an
insulated GND line 69 (refer to FIG. 6). An insulated earth line 71
is provided along the transmission cable 25. In addition, the
insulated earth line 71 may be included in the transmission cable
25.
The endoscope 100 includes a linear conductor 73 at the tip portion
27. A tip of the linear conductor 73 extends toward the lens unit
side with respect to the image sensor 29, and a proximal end
thereof passes through the insertion portion 15. In the linear
conductor 73, the conductor may be either a single line or a
stranded line. The materials of the conductor include, for example,
an aluminum alloy, a copper alloy, and the like. In the linear
conductor 73, the conductor may be insulatively covered with vinyl
chloride, polyethylene, or the like. A proximal end of the linear
conductor 73 passes through the inside of the sheath 43 in the
insertion portion 15. The linear conductor 73 may be connected to
the plug 17 as it is, may be connected to the insulated earth line
71 in the flexible portion 23, or may be connected to the plug 17
via the insulated earth line 71. In any case, the linear conductor
73 is connected to an insulated earth portion of a circuit 75 to be
insulated (refer to FIG. 6) via the plug 17.
A tip of the linear conductor 73 and the tip flange portion 33 are
separated from each other. Specifically, the tip of the linear
conductor 73 is disposed so as to be separated from, for example,
the angular tube portion 55 of the tip flange portion 33. A gap G
is secured between a rear end surface of the angular tube portion
55 and the tip of the linear conductor 73. The tip of the linear
conductor 73 is coated with, for example, a mold resin 49 having a
thickness substantially equivalent to the gap G on the rear end
surface of the angular tube portion 55, is inserted into the mold
resin 49, and is then fixed to the mold resin 49 with an adhesive
77.
Therefore, in the endoscope 100, the linear conductor 73 is fixed
with the adhesive 77 in a state where the tip of the linear
conductor 73 and the tip flange portion 33 are separated from each
other.
In the endoscope 100, as illustrated in FIG. 3, an outer periphery
of the lens unit 53 is molded by the mold portion 45. In the
endoscope 100 of Embodiment 1, the linear conductor 73 and the
adhesive 77 are simultaneously covered with the mold portion
45.
FIG. 5 is a view as seen from arrow A-A of FIG. 4.
Here, the tip of the linear conductor 73 is disposed between the
outer periphery of the circular lens unit 53 surrounded by an
angular outline (for example, a quadrangular outline) of the image
sensor 29, and corner portions of the image sensor 29. That is,
internal corner portions between corners of the angular tube
portion 55 and the internal diameter hole 59 are coated with the
mold resin 49, and the tip of the linear conductor 73 is fixed to
the mold resin 49 with the adhesive 77. In addition, four corner of
the angular tube portion 55 and four corners of the image sensor 29
are disposed in the same phases.
FIG. 6 is a block diagram schematically illustrating the
configuration of the endoscopic system 11 in a case where the
endoscope 100 of Embodiment 1 is used for medical applications.
In the endoscope 100, a front surface of the tip portion 27 serves
as a static electricity application portion (static electricity
application portion). That is, the tip flange portion 33 serves as
the application portion. In other words, when the endoscope 100 is
inserted into the examination target during use of (for example,
during examination or during surgery), static electricity flows
into the tip flange portion 33. The static electricity that has
flowed into the tip flange portion 33 flows into the linear
conductor 73 via the gap G by discharge, and is allowed to escape
from the linear conductor 73 serving as the insulated earth line 71
to the insulated earth portion of the circuit 75 to be insulated
via the plug 17. Accordingly, the application of the static
electricity to the image sensor (that is, the image sensor 29) is
suppressed.
The insulated earth portion is provided at the circuit 75 to be
insulated. The circuit 75 to be insulated can also be referred to
as a protected circuit for preventing an electric shock to a
patient. Additionally, by providing an insulated circuit 81 between
the circuit 75 to be insulated, and a secondary circuit 79 having a
signal processing unit (driven with DC 10 to 12 V) provided within
the video processor 13, a state where the circuit 75 to be
insulated and the secondary circuit 79 are electrically insulated
is secured. The secondary circuit 79 is connected to a primary
circuit 83 to be grounded.
Normally, a power supply device (medical insulation power source
unit) having reinforced insulation for medical applications, is
used for the primary circuit 83 used for medical apparatuses, and
the primary circuit 83 is connected to a commercial power source 85
(for example, AC 100 V).
In a case where the endoscope 100 is used as a medical endoscope,
it is necessary to consider preventing inflow of a leakage current
to a patient. For that reason, the linear conductor 73 that guides
the static electricity, and a patient contacting portion (for
example, the tip flange portion 33) are insulated from each other
by providing the gap G. The linear conductor 73 that guides the
static electricity is connected to the insulated earth portion that
sufficiently reduces the leakage current via the electrically
insulated circuit 81. In this way, the endoscope 100 protects the
image sensor 29 by installing the linear conductor 73 for guiding
the static electricity to allow the static electricity to escape
from the image sensor 29, between the static electricity
application portion and the image sensor 29 to allow the static
electricity to escape to the insulated earth portion.
Next, the operation of the above-described configuration will be
described.
In the endoscope 100 of Embodiment 1, the tip of the linear
conductor 73 extends toward the lens unit 53 side with respect to
the image sensor 29. For that reason, the dielectric breakdown
strength from a side surface of the lens unit 53 to the tip of the
linear conductor 73 can be made smaller that the dielectric
breakdown strength from the lens unit 53 to the image sensor 29.
The static electricity applied to the tip portion 27 due to the
difference in dielectric breakdown strength is discharged to the
tip of the linear conductor 73 while flowing into the image sensor
29 is suppressed. That is, by installing the linear conductor 73
that guides the static electricity between the static electricity
application portion and the image sensor 29, it is possible to
reliably allow the static electricity to escape to the insulated
earth portion within the circuit 75 to be insulated via the linear
conductor 73 serving as the insulated earth line, or the plug 17,
and the image sensor 29 can be exactly protected. In the endoscope
100, since the linear conductor 73 may be disposed to extend toward
the lens unit side with respect to the image sensor 29, the
structure becomes extremely simple. As a result, the manufacture is
facilitated, and particularly, a reduction in size and a reduction
in diameter is facilitated compared to a structure in which a
related-art projection portion or metallic pipe is provided as in
the above-described WO2013/031276.
Additionally, in the endoscope 100, it is possible to guide the
application of the static electricity to the tip flange portion 33
by providing the tip flange portion 33 having conductivity on the
front surface of the tip portion 27. For this reason, it is
possible to more reliably allow the static electricity to escape to
the insulated earth portion by carrying disposing the tip of the
linear conductor 73 in proximity to the tip flange portion 33.
Additionally, in the endoscope 100, the linear conductor 73 that
guides the static electricity, and the patient contacting portion
(particularly, the tip flange portion 33) are insulated from each
other by this separation. The linear conductor 73 that guides the
static electricity is connected to the earth portion that
sufficiently reduces the leakage current via the electrically
insulated circuit 81. Therefore, the endoscope 100 can sufficiently
reduce the leakage current to a patient in medical
applications.
Additionally, in the endoscope 100, since the linear conductor 73
is fixed to the tip flange portion 33 by the mold resin 49 and the
adhesive 77, a separation distance can be set with high accuracy in
a case where the tip of the linear conductor 73 is separated from
the tip flange portion 33. Additionally, in a case where the linear
conductor 73 is covered with the mold portion 45, the linear
conductor 73 can be fixed to a desired position in advance. Thus,
the positional deviation of the linear conductor 73 during pouring
of the mold resin can be suppressed to facilitate a molding
step.
Additionally, in the endoscope 100, particularly, in a case where
the optical fibers 39 for guiding light are disposed between a side
portion of the image sensor 29 and the outer periphery of the mold
portion 45, any interference between the linear conductor 73 and
the optical fibers 39 can be avoided. The linear conductor 73 can
be easily disposed or fixed while avoiding any interference with
the optical fibers 39.
Moreover, in the endoscope 100, the linear conductor 73 can be
reliably fixed to the tip portion 27 by embedding the linear
conductor 73 in the mold portion 45. For this reason, the endoscope
100 can enhance the fixed strength of the linear conductor 73
against the tension generated in the linear conductor 73 as the
insertion portion 15 is bent during operation.
Embodiment 2
Next, an endoscope 200 of Embodiment 2 will be described.
FIG. 7 is a block diagram schematically illustrating the
configuration of the endoscopic system 11 in a case where the
endoscope 200 of Embodiment 2 is used for industrial applications.
In addition, in Embodiment 2, the same members as the members
illustrated in FIGS. 1 to 6 will be designated by the same
reference signs, and duplicate description will be omitted.
In the endoscope 200 of Embodiment 2, the tip of the linear
conductor 73 and the tip flange portion 33 are electrically
connected to each other. The linear conductor 73 is conductively
connected to the angular tube portion 55 with, for example, solder.
Additionally, the conductive connection between the linear
conductor 73 and the angular tube portion 55 may be further firmly
fixed not only with solder but with the adhesive 77. The
transmission cable 25 includes a signal line 87, a power source
line 89, and a GND line 91. The linear conductor 73 serving as a
secondary earth line 93 is provided in the transmission cable 25.
In addition, the secondary earth line 93 may be included in the
transmission cable 25. The transmission cable 25 and the secondary
earth line 93 are connected to the secondary circuit 79 having a
secondary earth portion and the signal processing unit via the plug
17. The secondary circuit 79 is connected to the primary circuit 83
to be grounded. The primary circuit 83 is connected to the
commercial power source 85. The other configuration is the same as
the schematic block diagram (refer to FIG. 6) of the endoscopic
system 11 including the endoscope 100 of Embodiment 1.
According to the endoscope 200 of Embodiment 2, in the industrial
applications that can allow a certain leakage current, the static
electricity can be reliably guided by conducting the tip of the
linear conductor 73 to the static electricity application portion
(tip flange portion 33). The linear conductor 73 that guides the
static electricity can be connected to an earth portion having low
impedance. The industrial endoscope 200 can have a simpler
configuration compared to the medical endoscope 100, and can also
be easily manufactured.
Embodiment 3
Next, endoscopes 300 and 300A of Embodiment 3 will be
described.
FIG. 8 is a perspective view of main portions of a configuration
example in which the tip of the linear conductor 73 in the
endoscope 300 of Embodiment 3 is disposed in the circumferential
direction. In addition, in Embodiment 3, the same members as the
members illustrated in FIGS. 1 to 6 will be designated by the same
reference signs, and duplicate description will be omitted.
In the endoscope 300 of Embodiment 3, the tip of the linear
conductor 73 is formed along a portion of the lens unit 53 in the
circumferential direction. The other configuration is the same as
the endoscope 100 of Embodiment 1.
According to the endoscope 300 of Embodiment 3, since the tip of
the linear conductor 73 extends also in the circumferential
direction, the static electricity can be easily guided to the
linear conductor 73.
FIG. 9 is a perspective view of main portions of a configuration
example in which the tip of the linear conductor 73 in the
endoscope 300A of Embodiment 3 is disposed at the entire
circumference in the circumferential direction.
Additionally, in the endoscope 300A of Embodiment 3, the tip of the
linear conductor 73 is formed along the entire circumference of the
lens unit 53 in the circumferential direction. The other
configuration is the same as the endoscope 100 of Embodiment 1.
According to the endoscope 300A of Embodiment 3, since the tip of
the linear conductor 73 extends over the entire circumference of
the lens unit 53, the static electricity can be easily guided to
the linear conductor 73.
Embodiment 4
Next, an endoscope 400 of Embodiment 4 will be described.
FIG. 10 is a perspective view of main portions of a configuration
example in which a linear tip of the linear conductor 73 in the
endoscope 400 of Embodiment 4 is disposed outside the mold portion
45.
FIG. 11 is a perspective view of main portions of a configuration
example in which a circumferential tip of the linear conductor 73
in an endoscope 400A of Embodiment 4 is disposed outside the mold
portion 45. In addition, in Embodiment 4, the same members as the
members illustrated in FIGS. 1 to 6 will be designated by the same
reference signs, and duplicate description will be omitted.
In the endoscope 400 of Embodiment 4, an outer periphery of the
lens unit 53 is molded by the mold portion 45, and the tip of the
linear conductor 73 is disposed outside the mold portion 45. The
tip of the linear conductor 73 disposed outside the mold portion 45
may be exposed in a straight line as in the endoscope 400
illustrated in FIG. 10, and may be exposed along the circumference
of the lens unit 53 as in the endoscope 400A illustrated in FIG.
11. The other configuration is the same as the endoscope 100 of
Embodiment 1.
According to the endoscopes 400 and 400A of this embodiment, the
portions of the linear conductor 73 other than the tip is fixed by
the mold portion 45, and the tip of the linear conductor 73 is
disposed outside the mold portion 45. Thus, the guidance effect of
the static electricity can also be enhanced while the fixation
thereof is reliably performed.
Therefore, according to the endoscope 100, the endoscope 200, the
endoscope 300, the endoscope 300A, the endoscope 400, and the
endoscope 400A of the embodiments, a reduction in diameter can be
easily achieved with a simple structure while the image sensor 29
is protected by releasing static electricity.
Embodiment 5
Next, an endoscope 500 of Embodiment 5 will be described.
FIG. 12 is a block diagram schematically illustrating the
configuration of the endoscopic system in a case where the
endoscope 500 of Embodiment 5 is used for medical applications. In
addition, in Embodiment 5, the same members as the members
illustrated in FIGS. 1 to 6 will be designated by the same
reference signs, and duplicate description will be omitted.
In the endoscope 500 of Embodiment 5, a sufficient gap G (for
example, refer to the gap G illustrated in FIG. 4) is not provided
between the rear end surface of the angular tube portion 55 and the
tip of the linear conductor 73. Additionally, an electro static
discharge (ESD) suppressor 90 (an example of a surge absorber) is
inserted between the linear conductor 73 and the insulated earth
line 71, and the insulated earth portion.
The ESD suppressor 90 is an example of a surge absorber that is a
protective element four countermeasures against a high voltage, and
protects an electronic apparatus (that is, a circuit to be
protected) from static electricity by utilizing the characteristic
that the resistance value decreases abruptly if a high voltage,
such as the static electricity, is applied. Additionally, the ESD
suppressor 90 reduces the amount of a leakage current from the
apparatus of the endoscope 500 by utilizing the characteristic
having a large resistance value if a voltage lower than the static
electricity is applied.
FIG. 13A is a block diagram schematically illustrating a first
usage example of an ESD suppressor related to a comparative
example. FIG. 13B is a block diagram schematically illustrating a
second usage example of the ESD suppressor related to Embodiment
5.
As illustrated in FIG. 13A, an ESD suppressor 90z is disposed so as
to be inserted into the ground (GND) from a location as close to
the static electricity application portion as possible in a signal
line or a power source line to which the static electricity is
applied, as a general usage. Accordingly, in a case where a low
voltage is applied, the ESD suppressor 90z functions as a resistor
having a large resistance value, and causes a voltage or electric
current from a conductor 73z to be supplied to a circuit 29z to be
protected via the signal line or the power source line. On the
other hand, in a case where a high voltage, such as the static
electricity, is applied, the ESD suppressor 90z can allow the
static electricity to escape to the ground (GND), and can prevent
the static electricity from being applied to the circuit 29z so as
to protect the circuit 29z.
Meanwhile, as illustrated in FIG. 13B, in Embodiment 5, the ESD
suppressor 90 is inserted between the linear conductor 73 and the
insulated earth line 71, and the insulated earth portion of the
circuit 75 to be insulated. Accordingly, in a case where a low
voltage is applied, the ESD suppressor 90 functions as resistor
having a large resistance value, and can cut off the leakage
current from the apparatus of the endoscope 500 to reduce leakage
of the leakage current to the tip flange portion 33 serving as the
patient contacting portion. Additionally, when a high voltage, such
as the static electricity, is applied, the ESD suppressor 90
operates to allow the static electricity to escape from the linear
conductor 73 and the insulated earth line 71 to the insulated earth
portion of the circuit 75 to be insulated by utilizing the
characteristic that the resistance value is abruptly lowered.
Therefore, even in a case where a sufficient gap G (for example,
refer to the gap G illustrated in FIG. 4) is not provided between
the rear end surface of the angular tube portion 55 and the tip of
the linear conductor 73, the ESD suppressor 90 can suppress that
the static electricity is applied to a circuit (for example, the
image sensor 29) to be protected, such as a sensor. That is,
according to the endoscope 500 of Embodiment 5, by virtue of the
insertion of the ESD suppressor 90, a path along which the static
electricity is allowed to escape can be secured and insulation can
be guaranteed to reduce the leakage current.
In the endoscope 500) of Embodiment 5, the ESD suppressor 90
serving as the protective element that cuts off the leakage current
to the tip portion 27 is disposed between the linear conductor 73
and the circuit 75 to be insulated electrically insulated from the
tip portion 27. Accordingly, even if a sufficient gap G is not
provided at the tip (specifically, the rear end surface of the
angular tube portion 55 and the tip of the linear conductor 73) of
the endoscope 500, the ESD suppressor 90 is inserted before the
ground connection of the linear conductor 73. Accordingly,
insulation can be guaranteed to reduce the leakage current while
securing the path along which the static electricity is allowed to
escape.
Although the various embodiments have been described above
referring to the drawings, it is needless to say that the invention
is not limited to the embodiments related to the present
disclosure. Those skilled in the art will appreciate that various
modifications or alterations can be conceived within the scope set
forth in the claims and these also naturally fall within the
technical scope of the present disclosure. Additionally,
configurations in which respective constituent elements in the
above-described embodiments are arbitrarily combined may be adopted
without departing from the spirit of the invention.
The present disclosure is useful as endoscopes in which a reduction
in diameter of the insertion tip portion is facilitated with a
simple structure while the image sensor is protected by releasing
the static electricity.
The present invention is based upon Japanese Patent Application
(Patent Application No. 2017-150016) filed on Aug. 2, 2017, the
contents of which are incorporated herein by reference.
* * * * *